Vector modulators are used for transferring a digital baseband signal to a radio-frequency carrier. A modulated radio-frequency output signal is derived by adding output signals from two doubly balanced mixers which are controlled with the aid of a quadrature carrier signal.
Furthermore, polar modulators can be used for generating a modulated radio-frequency output signal, wherein the phase of such a modulated RF signal (RF—radio frequency) is modulated with the aid of a DPLL (digital phase locked loop) and the amplitude of such a modulated RF signal is modulated with the aid of a radio-frequency DAC mixer (DAC—digital-to-analogue converter).